Diametrically sliding vane compressor



Unite s oss sse DIAlvmTRIcALLY sLrnnic vANn coi/mnnsson Earl F. Hnbacker and Carl E. Boettcher, Evansville, Ind.,

This invention relates to a compressor.

In the ordinary compressor for compressing a fluid, of which a good example is the compressor used in a refrigerator, there is customarily provided a rotor head rotatable about an axis and provided with slots for containing slidable blades. The rotor head and blades rotate within a cylindrical bore that has an axis eccentric to the axis of rotation of the head so that fluid such as refrigerant will be trapped by the slidable blades between the rotor head and bore and will be compressed. Such a compressor is widely used and is shown in many patents of which an example is Patent 2,072,307, dated March 2, 1937.

In the present invention the rotor head is provided with a diametric slot in which is contained a pair of blades located in the opposite ends of the slot for engagement at their outer ends with the inner walls of the body that forms the cylindrical bore. The pair of blades have their inner ends overlapped so that the over-all blade length is increased without increasing the diameter of the rotor head.

One of the features of this invention is to provide in a compressor improved apparatus comprising a rotor head rotatable about an axis and provided with a diametric slot, a body having a cylindrical bore eccentric to said axis in which said rotor head is located, and a pair of blades located inthe opposite ends of said slot slidable relative to the siot for engagement at their outer ends with the body upon rotation of the rotor, the blades having their inner ends overlapping.

Other features and advantages of the invention will be apparent from the following description, taken in conjunction with the accompanying drawings. Of the drawings:

FIGURE l is a fragmentary perspective view partially in section of a portion of a compressor embodying the invention.

FIGURE 2 is a ybottom view illustrating the construction of the compressor in the vicinity of the rotor head and blades.

FIGURE 3 is a fragmentary perspective view of a rotor head and one blade illustrating a second embodiment of the invention.

FIGURE 4 is a fragmentary sectional view illustrating a third embodiment of the invention.

In the embodiment of FIGURES 1 and 2 the apparatus includes a rotor head mounted for rotation on a shaft 11 and rotating in a cylindrical bore 12 formed in a body 13. The head 10 is provided with a diametric slot 14 extending therethrough from one surface 15 where the shaft Il is located to the other surface 16 opposite to the shaft.

The head 10 and bore 12 are eccentric to each other with the head having an outer surface substantially tangential to the inner surface of the bore 12 as shown in FIGURE 2.

Slidably mounted in the diametric slot 14 are a pair of blades 17 having overlapping ends as illustrated in FIG- URE 2. Each blade 1'7 has one side surface 18 longer thanthe other side surface 19 with these two opposite side surfaces being parallel to each other and contacting the parallel sides of slot 14. In each blade 17 the long surface 18 is facing or is upstream to the force of rotation which is indicated in FIGURE 2 by the arrow 20.

,066,352 Patented Dec. 4, 1962 The side surfaces 1d and 19 of each blade 17 are oonnected by plane surfaces 21 to form overlapping wedge shapes.

In the embodiment of FIGURE 3 the rotor heed 110 is also provided with a slot 114. but for purposes of added strength the portions of the head on opposite sides of the slot 114 at the end surface opposite the shaft 111 are connected by a cross bridge or pin ZZ. This pin is located substantially on a diameter of the head 11d and is at about to the slot 114.

In the embodiment of FIGURE 3 only one blade 117 is illustrated although of course a pair of blades will be used in the manner shown in FIGURE 2. Each of the blades 117 is cut away on the bottom to provide a portion 23. ri'his cut away portion 23 on each blade extends around the pin 22 and permits full inward and outward movement of each blade without interference of the pin. Thus the inner edge 24 of the portion 23 will be adjacent the pin 22 when the blade 117 is at its innermost position.

FIGURE 4 illustrates a third embodiment of the present invention. A shaft 25 extends from the lower side of the rotor head 210 and is attached coaxially to head 210 in the same manner as upper drive shaft 2,11. QThe usual oil grooves 27 are provided in shafts 211 and 25 adjacent head 210. The head 210 is provided with a slot 214 in which blades (not shown) similar to blades-17 are movably mounted in the manner previously described. Body 213 is provided with a bearing recess 26 to support shaft 25. This method of support substantially strengthens the rotor head assembly and prevents any displacement of the rotor halves.

By employing overlapping blades as described here a longer blade can be used in the same size rotor head-10 or if desired the same over-all length of blade Acan be used with a smaller rotor head. This is true because the longer the over-all blade length the greater thepermissible blade extension. 0n the average it has been found that for maximum performance and minimum wear the maximum blade extension should be approximately 40% of the blade length. Therefore by overlapping the inner ends of the blades the effective length of each blade is increased so that a greater blade length 'can be projected. By using theblades of this invention, therefore, it is possible to increase the compressor capacity of any given compressor without varying the size of the rotor head by increasing the over-all blade length and by increasing the diameter of the bore, or with a compressor of equal capacity it is now possible to use a smaller rotor head without change in the diameter of the cylinder bore.

The rotor and blade construction of this invention provides improved performance with reduced wear. j In FIGURE 2 the bore diameter is indicated at D1 while the rotor head diameter is indicated at D2. By using the blades of this invention it is possible to have D1 smaller than in conventional compressors without loss of capaoity. Similarly D2 can be reduced without loss of 'capac` ity. Because of the greater permissible maximum'extension of the blades I7 or 117 it is now possible to reduce the size of the compressor without sacrilice of the capacity. Smilarly if desired it is possible to use the same size compressor and achieve an increased capacity. :Y

A very important factor resulting from the reduced diameters that are possible with the rotor and blades of this invention is the material reduction in frictional power loss within the compressor. The following formula is used as a general illustration of the total power loss, 'PT, in a rotary type refrigeration compressor: y

The quantities X, Y and Z are finite quantities, reg

3 generally constant. The term (11,) indicates the radius of the rotor head, the term (Dm) is the diameter of the cylinder bore, and h is cylinder height or distance between the end faces. The iirst term in tbe equation X(R,)4 indicates the frictional loss at the rotor faces. Notice that this term varies as the fourth power of the rotor head radius. Obviously, reducing the rotor head radius substantially decreases the rotor face frictional losses. Similarly, the second term of the equation Y(Dc,|)3/2h is substantially reduced when (Dcyl) is reduced or h is reduced. In the second term, irictional losses vary with the 3/2 power of cylinder diameter and are in proportion to cylinder height.

Having described our invention as related to the embodiments shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details of description, unless otherwise specified, but rather be construed broadly within its spirit and scope as set out in the accompanying claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are dened as follows:

1. In a compressor, apparatus comprising: a rotor head rotatable about an axis and having a diametric slot having parallel walls; a body having a cylindrical bore eccentric to said axis in which said rotor head is rotated; a pair of diametrically opposed blades in said slot, each blade having parallel sides, one of which is longer than the other, engaging said walls for sliding movement of the blades in said slot upon rotation of said rotor head,

the longer side being the leading side of each blade, and each blade having an outer end engaging said body bore; and overlapping adjacent oblique surfaces on the inner ends of the blades having unobstructed substantial clearance with respect to each other at all times throughout their overlapping extent, the oblique end surface on each blade extending between said blade sides.

-2. In the compressor as detned in claim 1, said rotor head further including a connecting bridge member extending across said slot, and each of said blades having a cutaway portion around said bridge member to permit said sliding movement, said cutaway portions remaining within said rotor head at all operational positions.

References Cited in the le of this patent UNITED STATES PATENTS 467,416 Irish Ian. 19, 1892 524,763 Ink Aug. 21, 1894 883,224 Neville Mar. 31, 1908 940,056 Pocock Nov. 16, 1909 1,164,897 Wellsteed Dec. 21, 1915 1,192,978 Belyea Aug. l, 1916 2,233,082 Kucher Feb. 25, 1941 2,459,071 Garrison Jan. 11, 1949 FOREIGN PATENTS 584,770 France Nov. 27, 1924 641,226 France Apr. 14, 1928 

